A catastrophic comet strike 13,000 years ago could have triggered the birth of civilization

Chelsea Gold at Space.com::

Scientists think that a cluster of comet shards may have smashed into Earth’s surface 13,000 years ago, in the most catastrophic impact since the Chicxulub event killed off Earth’s large dinosaurs about 66 million years ago. In a new study, a team led by Martin Sweatman, a scientist at the University of Edinburgh in Scotland, investigated the impact and how it could have shaped the origins of human societies on Earth.

While the first Homo sapiens emerged between 200,000 and 300,000 years ago, much farther in the past than this impact, the researchers found that this comet crash actually coincided with significant changes in how human societies self-organized.

I have sometimes wondered about this: For hundreds of thousands of years, humanity was a species of nomadic hunter-gatherers and small villages, groups no larger than a few dozen people. Changes were small, and happened excruciatingly slowly.

Then, 10 thousand+ years ago or so, things start changing fast — rapid changes that continue to this day. We get the emergence of agriculture, the first cities, and a few thousand years later, written language.

So why the sudden change? Maybe a cometary catastrophe?

Spaceships with warp drives are unnecessary to colonize a whole galaxy, according to recent computer simulations

George Dvorsky at Gizmodo:

A new computer simulation shows that a technologically advanced civilization, even when using slow ships, can still colonize an entire galaxy in a modest amount of time….

The new paper [in The American Astronomical Society], co-authored by Jason Wright, an astronomer and astrophysicist at Penn State, and Caleb Scharf, an astrobiologist at Columbia University, shows that even the most conservative estimates of civilizational expansion can still result in a galactic empire.

The simulation starts with a single technological civilization in a galaxy like ours, and results in the entire inner galaxy being settled in 1 billion years. “That sounds like a long time… ” says Dvorsky (um, because it is?) “… but it’s only somewhere between 7% and 9% the total age of the Milky Way galaxy.”

By comparison, writing was invented a mere 6,000 years ago.

The simulation throws around some other big numbers:

Migration ships are launched once every 10,000 years, and no civilization can last longer than 100 million years. Ships can travel no farther than 10 light-years and at speeds no faster than 6.2 miles per second (10 kilometers per second), which is comparable to human probes like the Voyager and New Horizons spacecraft.

“This means we’re not talking about a rapidly or aggressively expanding species, and there’s no warp drive or anything,” said Wright. “There’s just ships that do things we could actually manage to do with something like technology we can design today, perhaps fast ships using solar sails powered by giant lasers, or just very long-lived ships that can make journeys of 100,000 years running on ordinary rockets and gravitational slingshots from giant planets.”…

… our “galaxy is over 10 billion years old, so it could have happened many times over, even with those parameters.”